Hi Guys,
I have trolled all the forum posts and the net and have not been able to find any information on this internal steel vent pipe.
On rebuilding the bottom end of my engine having already fitted the oil pick up pipe/ strainer and torqued the mains and was about to fit the sump when I came across the oil vent pipe which I had misplaced and found was damaged on the end the goes into the upper part of the engine. I assumed this damage had occurred during storage as the engine has been apart longer than I care to mention. I carefully heated and reformed the end of this pie and fitted it to the engine. On refitting the sump I found it fouled on the sump and had to tap it further into the block and have obviously re-crumpled the end as it must have originally been fitted.
I have seen many images of later Lotus 907 engines and noticed this pipe is absent, was it discontinued on the later engines?
Is it necessary as the hole in the engine casting will still allow the sump to breathe.
I am amazed how rough the assembly of these cars were back in the 70's. How easy would it have been to trim this pipe by 1/8" and have this fit properly.
During my JH restoration have come across lots sub standard workmanship for what is supposed to be hand built car. For instance the amount of weld splatter on the engine mounting brackets that was just painted over. Can anyone enlighten me?

Vent Pipe:
It's used in the 2.0 907 in the Elite, Eclat & Esprit.
It is not in the 2.2 912 or 910
Lotus hasn't made new ones in decades, so if you need one, contact Lotusbits in the UK for a used one.http://lotusbits.com/

The 'star-shaped' spray shield behind the rear main seal was discontinued/ deleted in 1988. It was still listed in the Parts Manual, but a note off to the side said the item could be deleted. If you have it, use it. If you don't have one for your 907 Mk II, don't sweat it.

Thank you very much for your reply, you are a wealth of information, I have always learnt a lot from your past posts.
My bottom end with a 2.2 crank is now altogether, the vent pipe and star shaped rear seal deflector are fitted.
I find the deletion of both these items in the later engines very interesting.
Being an engineer, I always go by the saying that if you know how and why anything works then you can fix it, and although I can see how this pipe vents from the sump I still cannot fathom why the hole though both halves of the engine casing would not suffice. Do you think Lotus came up with the same line of thinking and the cost versus the necessity in production lead to the deletion of these two components?